Water quench method and apparatus

ABSTRACT

Method for liquid quench cooling a heated strand moving in a vertical path of travel by providing a variable height water column through which the strand passes. The column is completely supported by air under pressure so that there is no mechanical apparatus in contact with the heated strand until after it emerges from the water in the column. The apparatus includes a chamber provided with aligned openings in its top and bottom through which the strand passes with substantial clearance in a vertical path of travel. A cooling fluid is introduced into the chamber and is supported by air under pressure admitted to the chamber adjacent the bottom thereof and surrounding the bottom opening.

United States Patent Brown et al.

14 1 July 15,1975

[541 mg E METHOD AND FOREIGN PATENTS OR APPLICATIONS A 870,556 5/1958United Kingdom 266/3 R [75] inventors: Ronald D. Brown, Independence;

Marvm stark Lexmgtonr both of Primary ExaminerCharles E. Van HornAssistant Examiner-Michael W. Ball [73] Assignee: Armco SteelCorporation, Attorney, Agent, or FirmMelville, Strasser, Foster &

Middletown, Ohio Hoffman [22] Filed: Jan. 30, 1973 2l A l N 328 130 [57]ABSTRACT I I pp' 0" Method for liquid quench cooling a heated strandRelated [15- Application ata moving in a vertical path of travel byproviding a vari- [62] Division of Ser. No. 180,803, Dec. 15, 1971, Pat.No. a l height water olumn through which the strand 3.735.967. passes.The column is completely supported by air under pressure so that thereis no mechanical appara- [52] US. Cl. 427/444; 118/69; 148/156; ms incontact with the heated strand until after it 266/3 R; 427/398 emergesfrom the water in the column. [5 i] It". CI CZld l/GZ The apparatusincludes a chamber provided i [58] held Search 7/102 M1 102 alignedopenings in its top and bottom through which 7/102 114 the strand passeswith substantial clearance in a H4 B; 118/691 405; 266/3 R? verticalpath of travel. A cooling fluid is introduced 48/156 into the chamberand is supported by air under [56] Reierences and pressure admitted tothe chamber adjacent the bottom UNITED STATES PATENTS thereof andsurrounding the bottom opening. 3,036,825 5/l962 Eisenmenger 266/4 R3,727,895 4/1973 Wondergem ll8/69 4 Claims 3 Dm'mg 44 45 46 4\\\}\wgw.\\ \\\w I? r Q/Zh;

/4 lllllll WATER QUENCl-I METHOD AND APPARATUS This is a division ofapplication Ser. No. 180,503 filed Dec. 15, 1971, now US. Pat. No.3,735,967.

BACKGROUND OF THE DISCLOSURE This invention relates to the liquid quenchcooling of a heated strand, and particularly to a method and apparatusfor liquid quench cooling of the still molten coating in a hot dipmetallic coating operation. The invention is particularly adapted to theliquid quench cooling of a coated strand moving in a vertical path oftravel.

Hot dip metallic coating operations, generally considered, all involve apretreatment of the base metal strand. This pretreatment includes athorough cleaning of the surface of the strand and is intended to makethe surface of the strand receptive to the molten coating metal.

Following the pretreatment, the base metal strand is immersed into abath of molten coating metal. A variety of coating metals are now incommon use, including zinc and its alloys, aluminum and its alloys,terne, and the like.

These aspects of a metallic coating operation do not, per se, form apart of this invention. It will be understood, however, that these stepsgenerally recited above will be carried out prior to the practice ofthis invention.

The base metal strand, as it emerges from the coating metal bath, willcarry with it on its surface a quantity of still molten coating metal.This molten coating metal adhering to the strand may be subjected to avariety of well known finishing actions, including the use of exit rollsor gas jets. These finishing techniques serve to control the coatingweight or quantity of molten metal adhering to the strand and to improveits surface characteristics.

It is then necessary to solidify the molten coating prior to coiling orother processing of the strand.

Most modern hot dip metallic coating operations contemplate that thestrand emerge from the coating metal bath in a vertical path of travel.It is well recognized by the skilled worker in the art that the verticalpath of travel has certain advantages, the primary one being that theinfluence of gravity will not adversely affect coating concentricity.

Present solidification technique calls for the utilization of coolingair during a portion of this vertically upward travel. This air coolingis continued till the coating has solidified sufficiently to be run overa pulley or sheave at the top of the cooling tower. At this point, thecoated strand is generally turned into a horizontally disposed liquidquench trough.

Commercial experience has shown that forced air cooling is relativelyslow. As is recognized by the skilled worker in the art, this required arather long vertically upward path of travel above the bath in order toprovide enough time for solidification to take place.

The length of required vertical travel is also known to create alignmentproblems. That is, pulleys, guides, sheaves, and the like cannot bebrought into contact with the coating metal while it is still molten.Therefore, the vertical distance between guides is very substantial. Ithas also been recognized in the art that a more rapid cooling, indeed aquenching, of the molten coating adhering to the strand would bedesirable for several metallurgical reasons. First of all, it is wellknown that an alloying takes place at the interface between the basemetal and the coating metal. Holding the alloy growth to a minimum willgreatly improve coating adherance.

Secondly, it is believed that by quench cooling immediately afterfinishing, the coated surface is greatly improved, both in appearanceand texture of the coated surface.

Keeping the foregoing comments in mind, it is a primary object of thisinvention to provide a method and apparatus for the liquid quenchcooling of a heated strand moving in a vertical path of travel. It is amore specific object of this invention to provide in a hot dip coatingoperation, a liquid quenching method and apparatus which will, by itsmore rapid cooling effect, hold alloy formation to a minimum and improvecoating adherance.

It is a further object of the invention to provide a liquid quenchcooling method and apparatus which will improve the surfacecharacteristics of the coated product.

Still another object of the invention is to provide a method andapparatus for liquid quench cooling the molten metal coating on a basestrand which will greatly reduce the required vertical travel above thebath, thereby permitting better alignment of the strand pass line.

Still a further object of the invention is to provide a liquid quenchcooling method and apparatus which will utilize a relatively smallamount of actual coolant.

A further object of the invention is to provide a liquid quench coolingmethod and apparatus for a heated strand moving in a vertical path oftravel, which does not require apparatus contacting the strand surfaceuntil after the quenching is completed.

SUMMARY OF THE INVENTION In its broadest terms, this inventioncontemplates the suspension of a variable height water column throughwhich the heated strand passes in a vertical path of travel, by means ofa contained column of air under pressure.

In more specific terms, a chamber may be provided having top and bottomopenings aligned to define a vertical path of travel for the heatedstrand. Strand will pass through these aligned openings with substantialclearance. A coolant fluid is introduced into the chamber and suspendedby a column of air under pressure admitted at the base of the chamber.

DESCRIPTION OF THE DRAWING FIG. I is a side elevational view of anexemplary apparatus for carrying out the invention.

FIG. 2 is a cross sectional view along the line 2-2 of FIG. 1.

FIG. 3 is an enlarged view of the bottom portion of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT As already indicated, thisinvention relates to the liquid quench cooling of a heated strand, andparticularly to the quench cooling of a molten metallic coating on aheated strand moving in a substantially vertical path of travel. It willbe assumed that the surface of the base strand has been properlyprepared in accordance with well known practice, and that the propertimetemperature relationship during actual immersion is observed.

As also indicated earlier, it will be assumed that the coating apparatusin general is arranged to provide a generally vertical path of travelfor the strand upon emergence from the coating metal bath.

The embodiment illustrated in FIGS. 1 and 2 of the drawings showapparatus for the liquid quench cooling of a metallic coating on wire orcylindrical base stock. lt will of course be understood that theinvention is equally applicable to the liquid quench cooling of a basestock in strip form.

The apparatus includes a cylindrical member through which the wirehaving a still molten coating on its surface passes. The cylindricalmember may be rigidly affixed to any suitable supporting structure 12 asby the bolts 14.

At its lower end, the cylindrical member 10 is provided with a nozzlestructure indicated generally at 16. This nozzle structure may besecured to the cylindrical member 10 in any suitable manner. It will beseen that the nozzle includes the female portion 18 which has a centralbore extending all the way therethrough. This bore includes thelowermost cylindrical portion 200, and a smaller diameter cylindricalportion 20b defining therebetween a shoulder 200. The upper portion ofthe bore 20d is of generally frusto-conical configuration. It will beobserved that the female member 18 is provided in the embodiment shownwith the water dam 22 at its upper end.

The male member of the nozzle structure includes the generallycylindrical portion 24 having the enlarged end portion 24a. It will beobserved that the male member is received within the bore in the femalemember, with the portion 240 seated against the shoulder 20c. The twoportions of the nozzle structure just described may be suitably securedtogether in this position in any satisfactory manner.

It will be seen that the outside diameter of the cylindrical portion 24of the male member is somewhat smaller than the inside diameter of thebore 20b and 20d. in effect defining a plenum chamber therebetween. Itwill be seen that the upper end of the male member is tapered as at 26to define an annular nozzle opening between these members when assembledtogether as described.

The male member is provided with an internal bore 28 which is of a sizesuch that the coated wire can pass with substantial clearance. It willof course be understood that on the one hand, the clearance must begreat enough to insure against mechanically contacting the still moltencoating carried upward by the wire. On the other hand, too great aclearance about the coated strand will make it difficult to maintainsufficient pressure in the chamber as described hereinafter Air or othergas under pressure from a suitable supply is introduced into the plenumchamber just described by means of the connection 30, the annularchamber 32, and a plurality of radial ports 34 in the female portion 18.

A cooling liquid medium will be supplied to the interior of thecylindrical portion 10 through the inlet fitting 38. Adjacent its upperend, the cylindrical member 10 is provided with an overflow opening 40.

it is believed that operation of the apparatus thus far described shouldbe clear. Water or other suitable quenching medium is introduced intothe cylindrical member 10 via the fitting 38. Simultaneously, a supplyof air under pressure via the fitting 30, annular passage 32, radialpassages 34, and the plenum chamber will be introduced into the lowerend of the cylindrical member 10. This air under pressure will support acolumn of water within the cylindrical portion 10. Of course, the heightof the water column may be adjusted by varying water supply and/or airpressure. If desired, the water can be continuously recirculated throughthe cylindrical portion 10 by adjusting the top of the column to be ator above the overflow opening 40.

At the top of the cylindrical member 10 may be provided the guidestructure indicated generally at 42. This includes the spring loadedguide rollers 44 and 46. It will be noted that the apertures 48 and 50at the top and bottom, respectively, of the guide structure 42 are ofsufficient size to permit the coated strand to pass with substantialclearance.

In the event the quench cooling liquid medium within the cylindricalportion 10 is not recirculated, a sight glass indicated generally at 52may be provided so that the level of the water can be checked andmonitored.

An exemplary embodiment of the invention which has been utilizedsuccessfully in the quench cooling of aluminum coated wire gauge sizesfrom 12 to 4 included a cylindrical member 10 having an inside diameterof approximately 2 inches. The inside diameter of the internal bore 28was approximately k inch. Air at a pressure of 6 psi was supplied to thefitting 30, and was sufficient to support a water column 15 inches high.

It will be apparent that many modifications can be made withoutdeparting from the scope and spirit of the invention. Accordingly, nolimitations are intended except as specifically set forth in the claimswhich follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. The method of liquid quench cooling a coated strand moving in avertical path of travel without mechanically contacting said stranduntil said coating has completely solidified, comprising the steps of:

a. providing a vertical chamber having a bottom with an opening for thepassage of said strand therethrough with clearance and a top and with anopening aligned with said bottom opening for passage of said strandtherethrough;

b. supplying cooling liquid to said vertical chamber by inlet means atsaid bottom end;

ct providing a cooling liquid outlet adjacent said upper end;

d. supplying gas under pressure at said bottom end of said chamber andsubstantially in the direction of said vertical strand movement;

e. supporting said cooling liquid within said chamber and maintainingsaid opening in said chamber bottom free of said cooling liquid by saidgas under pressure; and

f. passing said strand through said top and bottom openings and said gasand liquid within said charn ber.

2. The method claimed in claim 1 including the step of continuallycirculating said cooling liquid from said inlet means, through saidvertical chamber and through said cooling liquid outlet by adjusting atleast one of the supply of said cooling liquid and said air pressure.

steps of causing said strand to enter said vertical chamber through saidcentral nozzle bore and supplying said gas under pressure to said nozzleplenum chamber.

1. THE METHOD OF LIQUID QUENCH COOLING A COATED STRAND MOVING IN AVERTICAL PATH OF TRAVEL WITHOUT MECHANICALLY CONTACTING SAID STRANDUNTIL SAID COATING HAS COMPLETELY SOLIDIFIED COMPRISING THE STEPS OF: A.PROVIDING A VERTICAL CHAMBER HAVING A BOTTOM WITH AN OPENING FOR THEPASSAGE OF SAID STRAND THERETHROUGH WITH CLEARANCE AND A TOP AND WITH ANOPENING ALIGNED WITH SAID BOTTOM OPENING FOR PASSAGE OF SAID STRANDTHERETHROUGH, B. SUPPLYING COOLING LIQUID TO SAID VERTICAL CHAMBER BYINLET MEANS AT SAID BOTTOM END, C. PROVIDING A COOLING LIQUID OUTLETADJACENT SAID UPPER END, D. SUPPLYING GAS UNDER PRESSURE AT SAID BOTTOMEND OF SAID CHAMBER AND SUBSTANTIALLY IN THE DIRECTION OF SAID VERTICALSTRAND MOVEMENT, E. SUPPORTING SAID COOLING LIQUID WITHIN SAID CHAMBERAND MAINTAINING SAID OPENING IN SAID CHAMBER BOTTOM FREE OF SAID COOLINGLIQUID BY SAID GAS UNDER PRESSURE, AND F. PASSING SAID STRAND THROUGHSAID TOP AND BOTTOM OPENINGS AND SAID GAS AND LIQUID WITHIN SAIDCHAMBER.
 2. The method claimed in claim 1 including the step ofcontinually circulating said cooling liquid from said inlet means,through said vertical chamber and through said cooling liquid outlet byadjusting at least one of the supply of said cooling liquid and said airpressure.
 3. The method claimed in claim 1 wherein said gas is air. 4.The method claimed in claim 1 wherein said bottom opening comprises anozzle having a central bore and a surrounding plenum chamber andincluding the steps of causing said strand to enter said verticalchamber through said central nozzle bore and supplying said gas underpressure to said nozzle plenum chamber.